KR100932825B1 - Method for producing anti-glare film, anti-glare film, anti-glare polarizer, display device and optical film - Google Patents

Abstract

The method for producing an anti-glare film according to the present invention comprises the steps of applying a coating comprising at least a resin, a solvent and fine particles on a substrate; Drying the paint applied to the substrate such that the Bernard cell structure is formed in the surface of the coating layer due to convection caused during volatilization of the solvent; Curing the resin contained in the paint in which the Bernard cell structure is formed therein to form an anti-glare layer having fine irregularities having an appropriate surface wave figure. The anti-glare layer has a white haze of 1.7 or less when measured by quantitatively determining the diffuse reflection component of diffused light incident on its surface.

Anti-glare film, base material, paint, resin, solvent, fine particles, Bernard cell structure

Description

METHOD FOR PRODUCING ANTI-GLARE FILM, ANTI-GLARE POLARIZER, DISPLAY APPARATUS AND OPTICAL FILM}

The present invention relates to a method of making an anti-glare film. In particular, the present invention relates to a method for producing an anti-glare film for use on the display surface of a display device such as a liquid crystal display device.

[Cross-Reference to Related Applications]

This application enjoys the benefits of priority of Japanese Patent Application No. 2007-064553 filed with Japan Patent Office on March 14, 2007 and Japanese Patent Application No. 2008-3463, filed with Japan Patent Office on January 10, 2008. The entire contents of which are hereby incorporated by reference.

In display devices such as liquid crystal display devices, an anti-glare film is formed on the display side and light is diffused by the film to impart anti-glare properties to the display device or to reduce reflection on the surface of the display device. do. Known anti-glare films impart anti-glare properties to the display device thanks to the fine irregularities formed in the surface of the film.

8 shows the configuration of a known anti-glare film 101. The anti-glare film 101 has a substrate 111 and an anti-glare layer 112 formed on the substrate 111. The anti-glare layer 112 comprises a resin containing fine particles 113 composed of amorphous silica or resin beads, the fine particles 113 being anti-glare layer 112 to form fine irregularities in the surface. Protrude from the surface of the. The anti-glare film 101 is formed by applying a coating material containing fine particles 113, a resin, a solvent and the like to the base material 111 and drying the applied coating material.

The method in which the paint containing the fine particles 113 is applied to the substrate for producing the anti-glare film is not expensive and provides good productivity, whereby this manufacturing method is widely used. However, the resulting anti-glare film 101 has anti-glare properties, but the shape of the protrusions of the individual fine particles 113 forming the surface irregularities of the film increases the haze value of the surface. The image undergoes a whitening phenomenon, whereby the contrast is lowered and the image definition is also lowered.

Since the anti-glare film is formed as the top layer on the display side of the liquid crystal display device, it is required to have an appropriate hardness for the hard coat. As a result, it is preferable to have a thickness as large as several micrometers to several tens of micrometers so that the influence of the base material 111 may not be affected. In order to form protrusions of the fine particles 113 in the surface of the anti-glare layer 112 having this thickness, fine particles having a particle diameter as large as the thickness of the layer need to be added. The use of fine particles having such large particle diameters leads to an increase in the appearance of glare (glare) on the surface of the anti-glare layer 112, thereby lowering the visibility of the display surface.

Under this situation, as shown in FIG. 9, the filling ratio of the fine particles 113 in the anti-glare layer 112 is reduced to increase the period of the surface irregularities of the anti-glare layer 112, Thereby improving the contrast ratio. However, in the anti-glare layer 112 having extended periods of surface irregularities with appropriate irregularities, flat portions are formed between the individual protrusions of the fine particles 113, so that the anti-glare properties of the film It becomes bad.

Anti-glare properties and high contrast ratios are opposite to each other and it is difficult to achieve both of these properties. In order to achieve both anti-glare properties and high contrast ratios and to prevent glare, a method has been proposed in which the surface irregularities of the anti-glare layer are controlled by shape transfer.

For example, Japanese Unexamined Patent Application Publication No. 2003-107205 (hereinafter referred to as "Patent Document 1") discloses a method for producing a shaped molded film having desired irregularities using an excimer laser beam processing apparatus. Japanese Unexamined Patent Application Publication No. 2006-154838 (hereinafter referred to as "Patent Document 2") discloses a method for producing a shaped molded film having desired surface irregularities by coating a resin on a matt polyethylene terephthalate (PET). . Prepared by transferring the desired irregularities to an ultraviolet-curable resin onto which the anti-glare film is applied onto the substrate using the shaped molding film formed by the above method, separating the shaped molding film and then curing the resin by ultraviolet irradiation. do.

However, in the method of forming the shape-molded film by the laser beam treatment described in Patent Document 1, the cost of the device is particularly high in the processing for a large area such as a television, and it is difficult to maintain high accuracy of the processing for the entire area. Furthermore, the manufacture of the anti-glare film by the shape transfer process includes placing the ultraviolet-curable resin in the die, curing the resin, and separating the cured resin, so that the line speed is not easily increased. , Mass-production is poor.

On the other hand, the method in which the paint containing fine particles is applied to the substrate is not expensive and provides good productivity as described above, but it is difficult to obtain an anti-glare film having both anti-glare properties and high contrast ratio. In order to solve the problem of contrast ratio or glare, the protrusions of the fine particles are covered with resin such that the anti-glare layer has a flat surface, but in this case, it is difficult to prevent reflection in the surface of the anti-glare layer, thereby Reduce glare-reflective properties In other words, it is difficult to achieve both anti-glare properties and high contrast ratios by controlling fine irregularities in the surface of the anti-glare layer.

Therefore, it is desirable to provide a method of making an anti-glare film having both good anti-glare and good contrast ratio at high productivity at low cost.

The inventors of the present invention have made extensive and intensive studies on how to produce anti-glare films having both anti-glare properties and high contrast ratios using a process in which a paint containing fine particles is applied to a substrate. As a result, the light scattering by the projections of the individual fine particles protruding from the surface of the anti-glare layer is not a controlled method, but a non-uniform distribution of surface tension caused during volatilization of the solvent contained in the paint (in terms of surface tension) Using the Marangoni convection due to non-uniformity, the Bernard cell structure is formed by convection in the paint and the meniscus of the liquid resin formed in the Bernard cell has the appropriate wave shape non-uniformity glare. It has been found that by means of the formation in the surface of the prevention layer, an anti-glare film having both anti-glare properties and high contrast ratio can be obtained.

According to one embodiment of the present invention, there is provided a method for producing an anti-glare film, the step of applying a paint to a substrate, the paint comprising at least a resin, a solvent and fine particles; Drying the coating applied to the substrate to form a Bernard cell structure in the surface of the coating layer by convection caused during volatilization of the solvent; A method is provided that includes curing a resin contained in a paint including a Bernard cell structure formed to form an anti-glare layer having fine irregularities having an appropriate surface wave figure. The anti-glare layer has a white haze of 1.7 or less when measured by quantitatively determining the diffuse reflection component of diffused light incident on its surface.

According to one embodiment of the present invention, the Bernard cell is formed by fine particles collected on a plane to form fine irregularities having appropriate wave shapes in the surface of the anti-glare layer, and the resulting anti-glare The appearance of white haze in the film can be reduced while diffusing light.

If the difference between the surface energy of the fine particles and the surface tension of the solvent is small, the fine particles coagulate markedly three-dimensionally during drying to form large irregularities in the surface, and the resulting film is accompanied by flashing It has high anti-glare properties and low contrast ratio. If this difference is large, the Bernard cell is formed by fine particles arranged on a plane even after drying to form an appropriate wave shape, and the resulting film has low anti-glare properties and high contrast ratio. If the difference is greater, the Bernard cell is less likely to form in the surface after drying, and the resulting film has many flat portions, and thus has low anti-glare properties. As such, in order to achieve the above anti-glare properties with the above relationship, the paint needs to be coated with a thickness smaller than the particle diameter of the fine particles, and in order to remove the flat portion, the fine particles will be added in large quantities. need. As a result, the resulting film has large white haze and low contrast ratio. By appropriately selecting the combination of the fine particles and the solvent such that the difference between the surface energy of the fine particles and the surface tension of the solvent is within a certain range, the fine particles can be properly aggregated on the plane, thereby forming an appropriate surface wavyness. Makes it possible.

The above summary of the present invention is not intended to describe each described embodiment or every implementation of the present invention. The following figures and detailed description more particularly exemplify these embodiments.

According to the present invention, there is provided a method for producing an anti-glare film having both good anti-glare and good contrast ratio with high productivity at low cost.

Embodiments of the present invention will now be described with reference to the accompanying drawings. In the following embodiments, in all the drawings, the same parts or parts are denoted by the same reference numerals.

(1) First embodiment

(1-1) Configuration of Liquid Crystal Display Device

Fig. 1 shows an example of the configuration of the liquid crystal display device in the first embodiment of the present invention. The liquid crystal display device comprises a liquid crystal panel 2 and a light source 3 provided directly under the liquid crystal panel 2, as shown in FIG. 1, wherein the liquid crystal panel 2 is anti-glare on its display side. It has a film 1.

The light source 3 supplies light to the liquid crystal panel 2 and has, for example, a fluorescent lamp (FL), an electroluminescence (EL) or a light emitting diode (LED). The liquid crystal panel 2 spatially adjusts the light supplied by the light source 3 to display the information. On both surfaces of the liquid crystal panel 2, polarizing sheets 2a and 2b are provided. The polarizing sheets 2a and 2b allow one of the polarized light components perpendicular to each other to the incident light to pass through the sheet and to block each other by absorption. The polarizing sheets 2a, 2b are arranged such that their transmission axes are perpendicular to each other, for example.

(1-2) Composition of Anti-glare Film

Fig. 2 shows an example of the configuration of the anti-glare film 1 in the first embodiment of the present invention. The anti-glare film 1 comprises a substrate 11 and an anti-glare layer 12 formed on the substrate 11 as shown in FIG. The anti-glare layer 12 comprises fine particles 13, wherein Bernard cells are formed in the surface of the anti-glare layer by convection caused in the paint during drying of the paint, and proper aggregation of the fine particles 13 is achieved. To form fine irregularities;

The anti-glare film 1 quantitatively determines the diffuse reflection component of diffused light incident on the surface of the anti-glare layer 12 of the anti-glare film 1 having black glass bonded to its rear surface. When measured, it has a white haze of 2.0 or less. This is because white turbidity of 2.0 or less can suppress a decrease in contrast ratio.

When nonpolar styrene fine particles mainly composed of styrene are used as the fine particles 13, it is preferable to use a solvent having a surface tension of 23 mN / m or less. In this case, surface properties with small white haze can be obtained while maintaining anti-glare properties. When acrylic-styrene fine particles composed mainly of acrylic-styrene copolymers containing acrylic components added to styrene are used, it is common that the desired surface properties of the above have a surface mount higher than the surface tension of the above (23 mN / m). It can also be obtained by using an aromatic, ketone or ester solvent used.

The anti-glare film 1 quantitatively determines the diffuse reflection component of diffused light incident on the surface of the anti-glare layer 12 of the anti-glare film 1 having a black acrylic sheet bonded to its rear surface. It has a white haze of 1.7 or less when measured by. This is because white turbidity of 1.7 or less can suppress a decrease in contrast ratio.

The appearance of white haze is perceived by detecting reflected light diffused by the surface of the anti-glare layer. As used herein, the term "white turbidity" refers to a value determined quantitatively by simulating the above phenomenon using a spectroscopic colorimeter such as an integral spherical spectroscopic colorimeter SP64 (manufactured and sold by X-Lite, Inc.). do.

materials

As a material for the substrate 11, for example, a transparent plastic film is used. Transparent plastic films such as known polymer films can be used. Specific examples of known polymer films include triacetylcellulose (TAC), polyester (TPEE), polyethylene terephthalate (PET), polyimide (PI), polyamide (PA), aramid, polyethylene (PE), polyacrylate (PAR), polyether sulfone, polysulfone, diacetyl cellulose, polypropylene (PP), polyvinyl chloride, acrylic resin (PMMA), polycarbonate (PC), epoxy resin, urea resin, urethane resin and melamine resin And, the transparent plastic film can be appropriately selected from these known polymer films. The substrate 11 has a thickness of 38 to 100 µm from the viewpoint of achieving excellent productivity, but the thickness of the substrate is not particularly limited to this range.

Anti-glare layer

The anti-glare layer 12 preferably has an average thickness in the range of three times the average particle diameter of the fine particles 13 to the average particle diameter of the fine particles 13. Specifically, the anti-glare layer 12 preferably has an average in the range of the average particle diameter of the fine particles 13 to 30 μm and more preferably in the range of the average particle diameter of the fine particles 13 to 15 μm. Has a thickness. If the average thickness is smaller than the average particle diameter of the fine particles 13, the white haze tends to increase. On the other hand, if the average thickness is greater than three times the average particle diameter of the fine particles 13, the resulting film is likely to undergo curling during curing of the resin in the manufacture of the film.

The anti-glare layer 12 has fine irregularities formed in its surface. The fine irregularities are different from the conventional irregularities formed from the fine particles 13 protruding from the anti-glare layer 12, and the substrate 11 is coated with a paint containing the fine particles 13 and then Bernard The cells are formed by drying them so that they form within the surface of the coating film by convection caused in the paint during drying. The irregular part is preferably an irregular part having a suitable wave length of a long period. For example, when the paint dries, the plurality of fine particles 13 are suitably impinged in the plane-inward direction by the convection induced in the paint and are mainly agglomerated in the plane-inward direction and thereby on the surface of the anti-glare layer. It is preferable to form the protruding portion. It is preferable that the fine particles 13 do not protrude from the anti-glare layer 12 and that the surface of the fine particles 13 is not exposed. When the surface of the fine particles 13 is exposed, fine irregularities containing components having an acute angle are formed due to the acute inclined portions of the fine particles 13, and the resulting surface diffuses light in different directions, thereby This causes the display screen to undergo bleaching.

3 is a diagram illustrating the root mean square slope. The square average roughness RΔq of the roughness curve, which is a parameter indicating surface roughness, is a parameter determined by obtaining an average of tilts within the micro-range, and is expressed by the following equation (1).

RΔq (or Rdq): squared mean slope of the roughness curve

Square Mean of Local Slope at Reference Length (dz / dx)

The square mean roughness R Δq, which is a parameter indicating the surface roughness of the anti-glare layer 12, is preferably 0.003 to 0.05 μm. If the root mean square roughness R? Q is less than 0.003 mu m, no anti-glare property is obtained. On the other hand, when the root mean square roughness R Δq is larger than 0.05 μm, the appearance of white haze is stronger and the contrast ratio is lowered. Measurement conditions of the root mean square roughness (RΔq) are in accordance with JIS B0601: 2001. Since there is a correlation between the squared mean roughness (RΔq) and the optical properties {contrast ratio (the appearance of white haze) and anti-glare properties}, high contrast ratio and anti-glare when the squared mean roughness (RΔq) is in the above range Both of the properties can be achieved.

The fine particles 13 are spherical or planar fine particles such as inorganic fine particles or organic free particles. The fine particles 13 preferably have an average particle diameter of about 5 nm to about 15 μm. If the average particle diameter is smaller than 5 nm, the anti-glare layer 12 has excessively fine surface roughness, resulting in poor anti-glare properties. On the other hand, if the average particle diameter is larger than 15 mu m, the anti-glare layer 12 has an excessively large thickness, and therefore, curling is likely to occur during curing of the resin in the production of the film. The average particle diameter of the fine particles 13 is determined by measuring the particle diameter, for example by Coulter Multisiser, and obtaining the average of the resulting data.

As the organic fine particles, for example, fine particles mainly composed of styrene (PS) or acrylic-styrene copolymer can be used. The organic fine particles may be either cross-linked or noncross-linked, and there is no specific limitation, and any organic fine particles composed of plastics or the like may be used. When slightly polar fine particles 13 composed of an acrylic resin are used as the fine particles 13, convection and agglomeration of the fine particles 13 in the paint are slightly difficult to be caused during the production of the film. In order to eliminate this disadvantage, the use of a solvent having a higher surface tension is required, but since this solvent has a high boiling point and the coating film is not easily dried, this solvent is difficult to handle in the manufacture of the film. Therefore, it is better to use nonpolar fine particles 13 composed of, for example, styrene. Furthermore, fine particles composed of acrylic-styrene copolymers are particularly preferred, where the surface energy of the copolymer can be varied by controlling the acrylic-styrene ratio in the synthesis of the copolymer and the solvent can be selected from a wide range of available solvents. Because there is.

The acrylic-styrene copolymer preferably contains 60 to 90 mass% of styrene component and 10 to 40 mass% of acrylic component. If the amount of the acrylic component is less than 10 mass%, the fine particles 13 are likely to aggregate three-dimensionally in the drying step described below, and the white haze in the resultant anti-glare film 1 Is increased. As a result, it is difficult to achieve both high contrast ratio and anti-glare properties as with conventional anti-glare films. On the other hand, if the amount of the acrylic component is greater than 40 mass%, it is difficult for the Bernard cell to be formed in the drying step described below, so that only poor anti-glare properties are obtained. As a result, it is difficult to achieve both high contrast ratio and anti-glare properties as with conventional anti-glare films.

As the inorganic fine particles, for example, crystalline silica or alumina can be used. The inorganic fine particles preferably have a nonpolar surface that is changed from the polar surface by treatment with an organic material. Controlled nonpolarity allows for proper convection or aggregation of the fine particles 13 to form the desired Bernard cell.

The anti-glare layer preferably has a filling ratio for fine particles of 4 to 10%. If the filling ratio is less than 4%, many flat portions are likely to be formed in the surface of the anti-glare layer, and as a result, hard to obtain anti-glare properties. On the other hand, if it is larger than 10% of the filling ratio, the dependence of the anti-glare property on thickness tends to be small, thereby making it difficult to control the anti-glare property by changing the thickness. The filling ratio means the ratio of the content of the fine particles (B) to the content of the resin (A) in the anti-glare layer (B / A × 100).

The anti-glare film 1 in the first embodiment of the present invention has fine irregularities continuously in the surface of the anti-glare layer thanks to the Bernard cell structure, so that the irregularities have different irregularities while maintaining the anti-glare properties. The light diffusion in the direction can be suppressed, thereby preventing the display screen from experiencing whitening.

(1-3) Method of manufacturing anti-glare film

Next, an example of a method of manufacturing the anti-glare film 1 having the above configuration will be described. In the method for producing the anti-glare film 1, a paint comprising fine particles 13, a resin, and a solvent is applied to the substrate 11, and convection is applied to form a Bernard cell in the surface of the coating film. Caused during drying, followed by curing.

Preparation of paint

First, for example, by means of a stirrer such as a disper or a dispersion mixer such as a bead mill to obtain a paint having the fine particles 13 in which the resin, the fine particles 13 and the solvent are dispersed therein. Are mixed together. In this example, light stabilizers, ultraviolet light absorbers, antistatic agents, flame retardants, antioxidants and the like may be further added as desired. Silica fine particles and the like can be added as viscosity modifiers.

As the solvent, for example, an organic solvent which dissolves the used resin raw material and has excellent wettability with the fine particles 13 and does not cause the substrate to undergo the whitening phenomenon can be used. In order to form the Bernard cell by the fine particles 13 arranged on the plane as described above, a solvent having a suitable surface tension with respect to the surface energy of the fine particles 13 to be used is selected. The difference between the surface energy of the organic fine particles and the surface tension of the solvent is preferably 8 to 13 mN / m. If the difference in surface tension is less than 8 mN / m, the fine particles 13 are prone to significantly three-dimensional aggregation, thereby causing the surface to suffer from glare and whitening. On the other hand, if the difference in surface tension is greater than 13 mN / m, the fine particles 13 are difficult to aggregate, and the resulting surface has poor anti-glare property. For example, when styrene fine particles are used as organic fine particles, a solvent having a surface tension of 23 mN / m or less at the application temperature is preferably used. In this case, a suitable Bernard cell is formed during the drying of the paint, thereby making it possible to obtain a suitable wavefront surface of the anti-glare layer 12. If the surface tension is outside of the above range, the fine particles 13 are agglomerated remarkably to remarkably form the surface irregularities of the anti-glare layer 12, so that the resulting film has excellent anti-glare properties. However, the surface suffers adverse whitening and glare. Examples of organic solvents include t-butanol having a surface tension of 20.0 mN / m at an ambient temperature of 20 ° C. and isopropyl acetate having a surface tension of 22.1 mN / m under ambient conditions at 22 ° C. When fine particles composed of acrylic-styrene copolymers having surface energy greater than styrene fine particles are used, commonly used organic solvents having higher surface tension such as ester solvents such as butyl acetate (surface tension: 24.8 mN / m ), Ketone solvents (surface tension: 25.4 mN / m) such as methyl isobutyl ketone, or aromatic solvents (surface tension: 27.9 mN / m) such as toluene can be used. Fine particles and solvents are not particularly limited as long as the above requirements are met.

The surface tension of the solvent is determined by, for example, the Wilhelmy method, in which the Wilhelmy plate and the liquid sample are in contact with each other to apply strain and the force pulling the Wilhelmy plate into the liquid is measured. As the measuring device, for example, Leo-Surf manufactured and sold by UBM Corporation, a dynamic surface tension measuring machine, can be used.

As the resin, an ionizing radiation-curable resin curable by irradiation with ultraviolet light or an electron beam or a thermosetting resin curable by heat is preferable, from the viewpoint of facilitating production, and a photosensitive curable by irradiation with ultraviolet light. Resin is the best. As the photosensitive resin, an acrylate resin such as urethane acrylate, epoxy acrylate, polyester acrylate, polyol acrylate, polyether acrylate or melamine acrylate may be used. Regarding the properties of the cured resin, a resin capable of producing a cured resin having excellent transparency to light from the viewpoint of achieving image transmittance, or a resin capable of producing a cured resin having a high hardness from the viewpoint of obtaining defect resistance Especially good, the resin can be appropriately selected. The ionizing radiation-curable resin is not limited to the ultraviolet curable resin and any ionizing radiation-curable resin can be used as long as it has light permeability, but it is remarkable in terms of color tone of transmitted light or transmitted light due to coloration and haze. Ionizing radiation-curable resins that do not change very well are preferred. Ionizing radiation-curable resins and thermosetting resins can be used individually or in combination.

The photosensitive resin is obtained by incorporating a photopolymerization initiator into an organic material capable of forming a resin such as a monomer (monomer), an oligomer (oligomer), or a polymer (polymer). For example, urethane acrylate resins are obtained by reacting polyester polyols with isocyanate monomers or prepolymers and reacting the resulting products with methacrylate monomers having hydroxyl functional groups.

In the first embodiment of the present invention, as the monomer, oligomer or polymer capable of forming a resin, it is preferable to use at least one of the monomer, oligomer or polymer which remains in the liquid state after drying the paint. Monomers, oligomers or polymers that remain in a liquid state after drying the paint, preferably having a relatively high viscosity to maintain the Bernard cell structure within the surface of the dried paint and to form a meniscus of liquid resin in the Bernard cell. . When using such monomers, oligomers or polymers, the surface-coated paint is dried to maintain fine irregularities with appropriate wave shape.

As the photopolymerization initiator contained in the photosensitive resin, for example, benzophenone derivatives, acetophenone derivatives, anthraquinone derivatives and the like can be used individually or in combination. In the photosensitive resin, components for facilitating film formation such as acrylic resin can be appropriately selected and incorporated.

Coating (application of paint)

Filtration is then applied to the paint obtained by the above process by a filter having a pore about twice the average particle diameter of the fine particles, and the paint is applied to the substrate 11. The paint is applied such that the average coating thickness after drying is 3 to 30 μm and more preferably 4 to 15 μm. If the thickness is smaller than the lower limit of the above range, it is difficult to obtain the desired hardness. On the other hand, if the thickness is larger than the upper limit of the above range, the resultant film is likely to undergo significant curling during curing of the resin. As to the method of applying the paint, there is no specific limitation, and a known coating method is used. Examples of known coating methods include methods using gravure coaters, bar coaters, die coaters, knife coaters, comma coaters, spray coaters or curtain coaters. The coating method is not limited to these, and any method of uniformly applying the paint to a predetermined thickness may be used.

Drying and formation of Bernard cell

The applied paint is dried to volatilize the solvent. In the first embodiment of the present invention, using Marangoni convection due to uneven distribution of surface tension caused during volatilization of the solvent, proper collisions and agglomeration of the fine particles 13 form Bernard cell structures within the surface of the coating layer. Is caused by convection in the paint. The meniscus of the liquid resin formed in the Bernard cell causes fine irregularities with appropriate wave shape to be formed in the surface of the coating layer.

When drying the paint, it is known that the fine particles 13 aggregate mainly in the plane-inner direction of the anti-glare layer 12 to form a two-dimensional aggregate and that the aggregate is present in the surface of the anti-glare layer without collection. Good. In this case, fine irregularities with successively suitable wave shapes are formed in the surface of the anti-glare layer, thereby achieving both anti-glare properties and high contrast ratio. The phrase "fine particles 13 agglomerate mainly in the plane-inner direction of the anti-glare layer 12" as used herein (1) all fine particles 13 are not laminated on each other in the thickness direction without glare Agglomeration only in the plane-inner direction of the barrier layer 12; Or (2) 1.7 when almost all fine particles 13 are agglomerated in the plane-inner direction and the residual fine particles are measured against the anti-glare film 1 with a black acrylic sheet attached to the rear surface [1.7]. To be stacked on one another in the thickness direction so as not to increase. All fine particles 13 ideally form two-dimensional aggregates, but some of the fine particles 13 can be separated from each other without forming aggregates so that white turbidity does not increase.

The agglomerates of the fine particles 13 are preferably covered with paint on the surface of the anti-glare layer 12. When the aggregate is covered, the fine particles 13 protrude from the anti-glare layer 12, and large angular components due to the curvature of the fine particles themselves are formed in the surface, so that an increase in white haze can be prevented. As used herein, the phrase "agglomerates are covered with paint" means that (1) the aggregates are completely covered with paint; Or (2) some of the fine particles 13 forming aggregates are covered with paint but with a white turbidity [up to more than 1.7 when measured against an anti-glare film 1 having a black acrylic sheet bonded to the rear surface. ] Means that it is not increased.

The formation of the Bernard cell structure is believed to be affected by the relationship between the surface energy of the fine particles 13 and the surface tension of the solvent. In order to control the Bernard cell structure, the surface tension of the solvent is preferably selected according to the surface energy of the fine particles 13. For example, when styrene fine particles 13 having a nonpolar surface are added in an appropriate amount, a solvent having a surface tension of 23 mN / m or less is preferably selected. If the surface tension of the solvent is greater than 23 mN / m, the fine particles 13 are remarkably agglomerated to remarkably form the surface irregularities of the anti-glare layer 12, resulting in the surface undergoing whitening and glare. . In the case of using the styrene fine particles 13, since the solvent which can be used is limited, it is not permitted to use an aromatic solvent such as a ketone solvent or toluene. As such, the use of acrylic-styrene copolymer microparticles having an acrylic component added to the styrene and having increased surface energy enables the use of a solvent such as toluene. Specifically, when acrylic-styrene copolymer fine particles mainly composed of 60 to 90 mass% of styrene component and 10 to 40 mass% of acrylic component are used, it is selected that a solvent having a surface tension of 27.9 mN / m or less is selected. Good. Examples of solvents having such a surface tension include t-butanol, isopropyl acetate, toluene, methyl ethyl ketone (MEK), isopropyl alcohol (IPA), methyl isobutyl ketone (MIBK), butyl acetate and dimethyl acetate. These solvents can be used individually or in combination.

In order to maintain the Bernard cell structure and the meniscus formed in the Bernard cell structure after drying, it is preferable to use a resin that remains in the liquid state after the drying step and before curing. This is because such a resin for the coating layer maintains an appropriate surface wave even after drying. If the paint contains a dry cured resin that changes to a solid state after drying, the surface of the anti-glare layer 12 formed on the flat substrate 11 is flat at the initial stage of drying and the inner side of the layer is completely at the drying stage. It is thought to remain flat according to the substrate 11 after drying.

As to the conditions for drying, there are no specific restrictions, and either air drying or artificial drying in which the drying temperature or drying time is controlled can be employed. It should be noted that if a stream of air is sent to the surface of the paint during drying, care must be taken to avoid forming a wind pattern in the surface of the coating layer. Once the wind pattern is formed, irregularities having the desired appropriate wave shape are not formed in the surface of the anti-glare layer 12, thereby making it difficult to achieve both anti-glare properties and high contrast ratio. The drying temperature and drying time may be appropriately determined depending on the boiling point of the solvent contained in the paint. In this case, it is preferable to select the drying temperature and drying time so that the substrate does not undergo deformation due to heat shrinkage while considering the heat resistance of the substrate 11.

Hardening

After drying, the ionizing radiation-curable resin is cured to form the anti-glare film 12. Examples of curing energy sources include electron beams, ultraviolet light, visible light and gamma rays, but from the viewpoint of ease of manufacture, ultraviolet light is preferred. For the ultraviolet light source, there is no particular limitation, and a high pressure mercury lamp, a metal halide lamp and the like are appropriately selected. For the irradiation dose, the irradiation dose can be appropriately selected so that the resin used is cured and the resin and the substrate 11 do not suffer from sulfidation. The atmosphere for irradiation may be appropriately selected depending on the curing of the resin, and the irradiation may be performed in air or in an inert gas atmosphere such as nitrogen gas, argon gas, or the like. When the thermosetting resin is used as the resin, the thermosetting resin is heated to form the anti-glare layer 12.

In the curing step, the resin having the Bernard cells formed therein is changed into a solid state, and then an anti-glare layer 12 having fine irregularities having an appropriate wave shape in the surface is formed.

Thus, the desired anti-glare film 1 is obtained.

In the first embodiment of the present invention, the Bernard cell is formed due to convection and aggregation of the fine particles 13 caused during volatilization of the solvent contained in the paint, so that the anti-glare layer 12 is suitable in its surface. It has fine irregularities with a wave shape, thereby achieving an anti-glare film 1 having both high contrast ratio and excellent anti-glare properties. By using the anti-glare film 1 in the liquid crystal display device, the image displayed on the liquid crystal display device can be improved in view of visibility.

(2) Second Embodiment

(2-1) Composition of anti-glare film

4 shows an example of the configuration of the anti-glare film 10 in the second embodiment of the present invention. The anti-glare film 10 is transparent comprising an anti-glare layer 12 having fine particles 13 formed on the substrate 11 and a dry cured transparent resin formed on the anti-glare layer 12. And a resin layer 14. The substrate 11, anti-glare layer 12 and fine particles are similar to those in the first embodiment, and fine irregularities are formed in the surface of the anti-glare layer 12 by convection and aggregation of the fine particles 13. .

The transparent resin layer 14 has fine irregularities formed in its surface. Thanks to the transparent resin layer 14 containing the dried and cured resin, only the inclination near the fine particles in the anti-glare layer 12 is maintained, while maintaining irregularities in the surface of the lower anti-glare layer 12. As a result, the resultant anti-glare film has the same white haze as the anti-glare film 1 in the first embodiment or more reduced than the anti-glare film 1 in the first embodiment, Thereby, excellent contrast ratio is achieved.

(2-2) Method of manufacturing anti-glare film

Next, an example of a method of manufacturing the anti-glare film 10 according to the second embodiment of the present invention will be described. In the method for producing the anti-glare film 1, a paint comprising a resin and a solvent is applied to the anti-glare layer 12 of the anti-glare film 1 in the first embodiment, and the transparent resin layer ( 14) is dried and cured to form. The method of forming the transparent resin layer 14 will be described below in detail.

Preparation of paint

First, for example, the resin and the solvent are mixed together to obtain a paint. In this example, light stabilizers, ultraviolet light absorbers, antistatic agents, flame retardants, antioxidants and the like may be further added as desired.

As for the solvent, there is no specific limitation as long as the resin raw material used is dissolved and the lower anti-glare layer 12 is not dissolved. As the solvent, an organic solvent such as t-butanol, toluene, isopropyl acetate, toluene, methyl ethyl ketone (MEK), isopropyl alcohol (IPA) or methyl isobutyl ketone (MIBK) can be used.

As the resin, for example, a resin which is changed into a solid state at least by drying is used. Resin that changes to a solid state by drying means a resin that is curable by drying (hereinafter, a resin that changes to a solid state by drying is often referred to as a "dry cured resin"), each of which has a molecular weight of 30,000 or more, for example. Preference is given to resins comprising at least one of monomers, oligomers or polymers having. When the paint contains a dry cured resin, the paint applied to the surface of the anti-glare layer is difficult to flow into the concave portion in the surface of the anti-glare layer during drying of the paint, thereby filling the concave portion with the paint. Is prevented, thereby making it possible to avoid planarization of the surface. Examples of dry cured resins include urethane resins, acrylic resins, styrene resins, melamine resins and cellulose resins. Although monomers, oligomers or polymers capable of forming ionizing radiation-curable resins or thermosetting resins can be used, the dry cured resins are not limited to these. As the ionizing radiation-curable resin, one having a reactive functional group such as an acrylic double bond is preferably used. As a thermosetting resin, what has thermosetting functional groups, such as a hydroxyl functional group, is used preferably. When using such resins, the reactivity is improved in terms of ionizing radiation-curing treatment or thermosetting treatment.

As the resin material, a mixture of at least one of the ionizing radiation-curable or thermosetting monomer, oligomer and polymer used in the first embodiment added to the above-mentioned dry cured resin can be used. Preferably, those which undergo a curing reaction with the material used as the dry cured resin are used.

Coating (application of paint)

The paint obtained by the above process is applied to the anti-glare layer 12. The paint is applied so that the dried average coating thickness is preferably 1/2 to 2 times the particle diameter of the fine particles 13 in the anti-glare layer, and the paint is applied to the protruding portion in the surface of the anti-glare layer 12. It is good to cover. As to the method of applying the paint, there is no specific limitation, and a known coating method similar to that in the first embodiment is used. By applying the paint to the anti-glare layer 12 uniformly to a predetermined thickness, fine irregularities equivalent to those in the surface of the anti-glare layer 12 are formed in the surface of the coating layer.

Drying and curing

The applied paint is dried and cured to obtain a transparent resin layer 14 having fine irregularities having an appropriate wave shape in its surface. In order to form fine irregularities having appropriate wave shapes in the surface of the transparent resin layer 14, the paint preferably contains at least a dry cured resin as described above. When a paint that does not contain any dry cured resin material, i.e. a paint containing only monomers, oligomers or polymers remaining in the liquid state after drying, is applied to the anti-glare layer 12, the resinous material is applied to the anti-glare layer 12 After filling and prior to completion of drying to fill the concave portion in the surface of), the surface is flattened, whereby the resulting film has poor anti-glare properties. Furthermore, the protruding portion in the surface of the anti-glare layer 12 remains as a protruding portion which causes the surface to be significantly roughened. When the paint contains a dry cured resin, the dried surface formed at the initial stage of the drying of the paint covers the anti-glare layer 12 of a suitable surface wavyness to prevent planarization thereby forming a more suitable wavy component. I think.

When the ionizing radiation-curable resin is contained as a resin, the resin is cured by ionizing radiation to form a transparent resin layer. When the thermosetting resin is contained, the resin is cured by heating to form the transparent resin layer 14.

Thus, the desired anti-glare film is obtained.

In the second embodiment of the present invention, fine irregularities having an appropriate wave shape equivalent to that of the anti-glare layer 12 or finer irregularities having an appropriate wave shape formed in the surface of the anti-glare layer 12 are provided. It is formed in the surface of the transparent resin layer 14. Therefore, by using the anti-glare film 10 in display devices such as liquid crystal displays, plasma displays, electroluminescent displays, or cathode ray tube (CRT) displays, an anti-glare property with superior contrast ratio than that obtained in the first embodiment is obtained. Can be achieved while maintaining the visibility, the visibility can be further improved.

Yes

In the following, embodiments of the present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

A 100 m continuous anti-glare film is prepared by continuous coating using a gravure coater as follows.

First, 200 g of styrene fine particles having a particle diameter of 5 to 7 μm and an average particle diameter of 6 μm, 4,000 g of ultrasonic curing as a resin material, a liquid 4-functional urethane acrylic oligomer, and 200 g as a photoreaction initiator. Irgacure 184 (manufactured and sold by Ciba-Geigy) is added to 6,000 g of t-butanol having a surface tension of 20.0 Nm / m at a coating temperature of 20 ° C. as a solvent and stirred to prepare a paint Then, the prepared paint is filtered using a 10-μm mesh filter.

The filtered paint is then applied to triacetylcellulose (TAC) having a thickness of 80 μm by a gravure coater at an application rate of 20 m / min. The resulting film is dried in a drying oven having a length of 30 m at a drying temperature of 80 ° C. In this case, using Marangoni convection due to a non-uniform distribution of surface tension caused during volatilization of the solvent, proper impingement and agglomeration of the fine particles is applied to the convection in the paint to form a Bernard cell structure within the surface of the coating layer. Is caused by The meniscus of the liquid resin formed in the Bernard cell causes fine irregularities having an appropriate surface wave shape to be formed in the surface of the coating layer. Subsequently, the film is continuously transferred into an ultrasonic curing oven, and the film is subjected to ultraviolet light under conditions at 160 W and at a dose of 300 mJ / cm 2 to form an anti-glare layer having a dried average coating thickness of 6 μm. Light is irradiated.

Example 2

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the dried coating thickness was 8 μm.

Example 3

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the dried coating thickness was 12 μm.

Example 4

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the dried coating thickness was 15 μm.

Example 5

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the dried coating thickness was 18 μm.

Example 6

An anti-glare film was obtained in substantially the same manner as in Example 1 except that isopropyl acetate having a surface tension of 22.1 Nm / m at a coating temperature of 22 ° C. was used as the solvent.

Example 7

1,000 g of dry cured acrylic polymer having a molecular weight of 50,000 as the resin material was used in 5,000 g of methyl isobutyl ketone (MIBK) having a surface tension of 25.4 Nm / m at a coating temperature of 25 ° C. as a solvent to prepare the paint. Is dissolved, and then the paint is applied to the anti-glare layer of the anti-glare film in Example 1 by means of a gravure coater, and the resin is cured to form a transparent resin having a dried average coating thickness of 6 μm. It is dried in a drying oven at 80 ° C. to obtain an anti-glare film.

Example 8

Anti-glare film in substantially the same manner as in Example 1 except that the fine particles were converted to fine particles consisting of an acrylic-styrene copolymer (acrylic: 10 mass%; styrene: 90 mass%) and the solvent was changed to toluene. Is obtained.

Example 9

Substantially the same manner as in Example 1 except that the fine particles were converted to fine particles consisting of an acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent was changed to methyl ethyl ketone (MEK). An anti-glare film is obtained.

Example 10

Anti-glare in substantially the same manner as in Example 1 except that the fine particles are converted to fine particles consisting of acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent is changed to butyl acetate A film is obtained.

Example 11

Anti-glare film in substantially the same manner as in Example 1, except that the fine particles were converted to fine particles consisting of an acrylic-styrene copolymer (acrylic: 30% by mass; styrene: 70% by mass) and the solvent was changed to MIBK. Is obtained.

Example 12

Example 1 except that the fine particles were converted to fine particles consisting of acrylic-styrene copolymer (acrylic: 30% by mass; styrene: 70% by mass) and the solvent was changed to toluene with a surface tension of 27.9 mN / m. An anti-glare film is obtained in substantially the same way.

Example 13

Anti-glare in substantially the same manner as in Example 1, except that the fine particles are converted to fine particles consisting of an acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent is changed to dimethyl carbonate. A film is obtained.

Example 14

The fine particles were turned into fine particles consisting of an acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent was changed to a mixed solvent containing 40 parts by weight of toluene and 60 parts by weight of dimethyl carbonate. Except for the anti-glare film obtained in substantially the same manner as in Example 1.

Example 15

The fine particles were converted into fine particles composed of acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent was changed to a mixed solvent containing 60 parts by weight of toluene and 40 parts by weight of dimethyl carbonate. Except for the anti-glare film obtained in substantially the same manner as in Example 1.

Example 16

Except that the fine particles are turned into fine particles consisting of an acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent is changed to a mixed solvent containing 80 parts by weight of toluene and 20 parts by weight of MEK. The anti-glare film is obtained in substantially the same manner as in Example 1 below.

Example 17

The fine particles were turned into fine particles consisting of acrylic-styrene copolymer (acrylic: 30% by mass; styrene: 70% by mass) and the solvent was changed to a mixed solvent comprising 60 parts by weight of butyl acetate and 40 parts by weight of dimethyl carbonate Except for the anti-glare film is obtained in substantially the same manner as in Example 1.

Example 18

The fine particles were converted into fine particles composed of acrylic-styrene copolymer (acrylic: 30 mass%; styrene: 70 mass%) and the solvent was changed to a mixed solvent containing 60 parts by weight of MIBK and 40 parts by weight of dimethyl carbonate. Except for the anti-glare film obtained in substantially the same manner as in Example 1.

Example 19

Anti-glare film in substantially the same manner as in Example 1 except that the fine particles were converted to fine particles consisting of an acrylic-styrene copolymer (acrylic: 40% by mass; styrene: 60% by mass) and the solvent was changed to MIBK. Is obtained.

Example 20

Example 1 except that the fine particles were converted to fine particles consisting of acrylic-styrene copolymer (acrylic: 40% by mass; styrene: 60% by mass) and the solvent was changed to toluene with a surface tension of 27.9 Nm / m. An anti-glare film is obtained in substantially the same way.

Example 21

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the amount of styrene fine particles was changed to 160 g.

Example 22

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the amount of styrene fine particles was changed to 400 g.

Example 23

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the amount of styrene fine particles was changed to 600 g.

Example 24

An anti-glare film is obtained in substantially the same manner as in Example 1 except that styrene fine particles having an average particle diameter of 4 μm are used and the average coating thickness after drying is 4 μm.

Example 25

An anti-glare film is obtained in substantially the same manner as in Example 1 except that styrene fine particles having an average particle diameter of 8 μm are used and the average coating thickness after drying is 8 μm.

Example 26

An anti-glare film is obtained in substantially the same manner as in Example 1 except that styrene fine particles having an average particle diameter of 10 μm are used and the average coating thickness after drying is 10 μm.

Comparative Example 1

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the dried thickness was 4 μm.

Comparative Example 2

An anti-glare film is obtained in substantially the same manner as in Example 1 except that the amount of styrene fine particles is 120 g.

Comparative Example 3

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the coating thickness after drying was 5 μm.

Comparative Example 4

An anti-glare film was obtained in substantially the same manner as in Example 1 except that MIBK was used as the solvent.

Comparative Example 5

An anti-glare film was obtained in substantially the same manner as in Example 1 except that toluene was used as the solvent.

Comparative Example 6

An anti-glare film was obtained in substantially the same manner as in Example 1 except that acrylic fine particles having an average particle diameter of 6 μm were used as the fine particles.

Comparative Example 7

An anti-glare film was obtained in substantially the same manner as in Example 1 except that the fine particles were changed to fine particles composed of acrylic and the solvent was changed to MIBK.

Comparative Example 8

An anti-glare film was obtained in substantially the same manner as in Example 6 except that the fine particles were changed to fine particles composed of an acrylic-styrene copolymer (acrylic: 75% by mass; styrene: 25% by mass).

Comparative Example 9

An anti-glare film was obtained in substantially the same manner as in Example 6 except that the fine particles were changed to fine particles consisting of an acrylic-styrene copolymer (acrylic: 55% by mass; styrene: 45% by mass).

Comparative Example 10

An anti-glare film was obtained in substantially the same manner as in Comparative Example 5 except that the thickness was changed to 4 μm.

Comparative Example 11

An anti-glare film was obtained in substantially the same manner as in Comparative Example 5 except that the amount of fine particles was changed to 800 g and the thickness was changed to 4 μm.

Comparative Example 12

An anti-glare film is obtained in substantially the same manner as in Example 1 except that a dry cured acrylic polymer having a molecular weight of 50,000 is used as the resin material and dried at 80 ° C.

Comparative Example 13

1,000 g of liquid 4-functional urethane acrylic oligomer as a resin material is dissolved in 5,000 g of methyl isobutyl ketone (MIBK) as a solvent to prepare the paint, and then the paint is subjected to the gravure coater in Example 1 160 to form a transparent resin layer applied to the anti-glare layer of the anti-glare film, dried in a drying oven at 80 ° C. such that the solvent was volatilized, and then having an average coating thickness after drying of 6 μm. Ultraviolet light is irradiated in the ultraviolet curing oven at W and under conditions at an irradiation dose of 300 mJ / cm 2, thereby obtaining an anti-glare film.

Evaluation of roughness

For each anti-glare film obtained as described above in Examples 1-26 and Comparative Examples 1-13, the surface roughness was measured and the roughness curve was obtained from the resulting two-dimensional cross-sectional curve The root mean square roughness RΔq of the roughness curve is determined as the roughness parameter by calculating. The results are recorded in Table 1. The conditions for the measurement comply with JIS B0601: 2001. The measuring device and the conditions for the measurement are shown below.

Measuring Device: Automatic Microfigure Measuring Apparatus Surfcoder ET4000A (manufactured and sold by Kosaka Laboratories Limited)

λc = 0.8; Evaluation length: 4 mm; Cut Off:?

Anti-glare properties

For each anti-glare film in Examples 1 to 26 and Comparative Examples 1 to 13, evaluation of anti-glare property is performed. Specifically, fluorescent illumination with shaded fluorescent lamps is reflected from the anti-glare film and the reflection is evaluated according to the following criteria. The results are recorded in Table 1.

(Double-circle): The outline of a fluorescent lamp cannot be observed. (Two fluorescent lamps are observed as a single lamp.)

(Circle): A fluorescent lamp can be observed to some extent, but the outline is not clear.

X: The fluorescent lamp is reflected as it is.

White turbidity

For each anti-glare film in Examples 1 to 26 and Comparative Examples 1 to 13, white haze is measured. Specific methods of measuring white haze will be described below. First, in order to eliminate the effect of reflection from the back surface to evaluate the diffuse reflection of the anti-glare film itself, the back surface of the anti-glare film is bonded to the black glass through the adhesive. Then, using the integrated spherical spectroscopic colorimeter SP64 (manufactured and sold by X-Lite, Inc.), the diffused light is irradiated to the surface of the sample and the reflected light is reflected to the normal to the sample. The measurement is performed by a d / 8 ms optical system measured by a detector positioned in the direction of. For the measured value, the SPEX mode in which only the diffuse reflection component except for the specular component is detected is employed, and the measurement is performed at a detection observation angle of 2 ms. This experiment confirmed that there was a correlation between the white haze measured by the above method and the visually perceived white haze. The results are recorded in Table 1.

For each anti-glare film in Examples 1 to 26 and Comparative Examples 1 to 13, a black acrylic sheet (made by Acrylite L 502, Mitsubishi Rayon Company, Limited) bonded to the rear surface via an adhesive and White turbidity of the anti-glare film with the (sold) is determined by calculating by the following equation (2). The results are recorded in Table 1. The white haze measured for the black acrylic sheet to which no anti-glare film is attached is 0.2.

y = 1.1039 x-0.4735 (2)

As mentioned above, there is a correlation between the white haze measured by the above method and the visually perceived white haze, the correlation being that when the above-determined value (Y value) is greater than 1.7% It was confirmed that white turbidity was reduced when perceived and this value was 1.7% or less, and almost no white turbidity was detected when this value was 0.8% or less. The introduction of equation (2) above will be explained later.

Cohesion in the plane-inner direction

The state of the aggregate of organic fine particles is examined under an optical microscope. Samples in which the organic fine particles are aggregated in the plane-inner direction are evaluated as "o", and samples in which the organic fine particles are not aggregated or are three-dimensionally aggregated are evaluated as "x". Among the anti-glare films in Examples 1 to 26 and Comparative Examples 1 to 13, typically, for the anti-glare films in Examples 1 and 5, surface photographs are shown in FIGS. 5 and 6 It is.

Meniscus formation

The surface shape is examined under an optical microscope in differential interference mode to examine whether the portion between the cells is flat or inclined. In the alternative, the surface is inspected through a cofocal image obtained by a laser microscope (manufactured and sold by Lasertec Corporation) to examine whether the portion between the cells is flat or inclined.

In Table 1, white turbidity A and white turbidity B respectively indicate the numerical values measured as follows.

White turbidity A: White turbidity measured for anti-glare films with black glass bonded to the back surface.

White turbidity B: White turbidity measured for anti-glare film with black acrylic sheet bonded to the back surface.

In Table 1, for dry curing for the resin, the symbol "x" indicates that the applied paint remained in the liquid state without curing after the drying step, and the symbol "○" indicates that the applied paint cured after the drying step. And the symbol "-" indicates that there is no transparent resin layer.

In Table 1, the filling ratio means the ratio of the content of the fine particles (B) to the content of the resin (A) in the anti-glare layer (B / A × 100).

The numerical values in Examples 1 to 26 and Comparative Examples 1 to 13 are individually determined as follows.

Average thickness of the anti-glare layer

The average thickness of the anti-glare layer is measured using a contact thickness meter (manufactured and sold by Tessa Corporation).

Average particle diameter of fine particles

The average particle diameter of the fine particles is determined by measuring the particle diameter with a Coulter multisizer and obtaining the average of the resulting data.

Solvent surface tension

The surface tension of the solvent is determined by, for example, the Wilhelmi method in which the Wilhelmi plate and the liquid sample are in contact with each other to apply strain and the force pulling the Wilhelmi plate into the liquid is measured. As the measuring device, Leo-Surf manufactured and sold by UBM Corporation, a dynamic surface tension measuring machine, is used. The measurement is performed under conditions such that the solvent temperature and the ambient temperature are the same. Specifically, the solvent is left in the atmosphere at an atmosphere temperature of 25 ° C., the solvent temperature reaches 25 ° C., and then the surface tension of the solvent is measured.

Surface energy of fine particles

The fine particles are pressed in the form of a plate by a press machine, and then the liquid is placed on the resulting surface of the plate to determine the critical surface tension, and the determined value is used as the surface energy of the fine particles. The measurement is performed in an atmosphere at 25 ° C. as above measurement of the surface tension of the solvent.

From Table 1, the following study results are obtained.

Anti-glare film and acrylic (10 mass%) in Examples 1 to 7 and Examples 21 to 26, wherein fine particles composed of styrene were used in the anti-glare layer and a solvent having a surface tension of 23 mN / m or less was used. Fine particles consisting of) -styrene (90 mass%) copolymer, acrylic (30 mass%)-styrene (70 mass%) copolymer or acrylic (40 mass%)-styrene (60 mass%) copolymer For the anti-glare film in Examples 8 to 20, the squared mean slope RΔq is in the range of 0.003 to 0.05, and both of the anti-glare property and the white haze are excellent. Anti-glare films in Comparative Examples 1 and 3 where the dried coating thickness is smaller than the average particle thickness of the fine particles and glare in Comparative Examples 4 and 5 where the surface energy of the fine particles is relatively smaller than the surface tension of the solvent For the prevention film, the RΔq value is large, so the anti-glare property is excellent, but the white haze is large and the contrast ratio is lowered. On the other hand, for the anti-glare films in Comparative Examples 6 to 10 in which the surface energy of the fine particles is relatively larger than the surface energy of the solvent, the RΔq value is small, so that the white haze is small, but the anti-glare property is poor. . In Comparative Example 11, in which the amount of fine particles is increased and the dried coating thickness is smaller than the average particle diameter of the fine particles, the anti-glare film has anti-glare properties and large white haze as in the conventional anti-glare film. For the anti-glare film in Comparative Example 12 in which a dry cured resin is used, since the RΔq value is small, the white haze is small, but the anti-glare property is poor. As can be seen from Comparative Example 2, when the amount of the fine particles is 3% by mass, since the flat portion is increased, the white haze is small, but the anti-glare property is hard to be obtained. Therefore, as can be seen from Examples 21 to 23, the amount of fine particles is preferably 4 mass% or more.

When styrene fine particles having a surface energy of 33 mN / m or acrylic fine particles having a surface energy of 40 mN / m are used, the difference between the surface energy of the fine particles and the solvent surface tension is small, as can be seen from Comparative Example 4. As can be seen, when the difference between the surface energy of the fine particles and the surface tension of the solvent is less than 8 mN / m, the fine particles are significantly 3-dimensionally aggregated during drying to form significant surface irregularities, and as a result The resulting film has glare, high anti-glare properties and low contrast ratio.

When this difference is large, as can be seen in Examples 1 and 6, the difference between the surface energy of the fine particles and the surface tension of the solvent is in the range of 8 to 13 mN / m, and the Bernard cell has a suitable surface wave It is formed due to the fine particles arranged on the plane even after drying to form a film, and the resulting film has a low anti-glare property and a high contrast ratio.

When the difference is greater, as seen in Comparative Examples 6 and 10, the difference between the surface energy of the fine particles and the surface tension of the solvent is greater than 13 mN / m, and the Bernard cell is formed in the surface after drying. It is difficult to prevent, and the resultant film has many flat portions, and thus has low anti-glare properties. As such, in order to achieve the anti-glare properties while having the above relationship, the paint needs to have a thickness smaller than the particle diameter of the fine particles, and to remove the flat portion, the fine particles need to be added in large quantities. Do. As a result, the resulting film has large white haze and low contrast ratio.

As is evident from the above results, by appropriately selecting the difference between the surface energy of the fine particles and the surface tension of the solvent and using a resin that does not cure after drying, formation of the Bernard cell in the surface of the anti-glare layer is avoided. It is controlled to obtain the desired roughness, thereby making it possible to obtain an anti-glare film with reduced white haze while maintaining anti-glare properties.

From Example 7, it was found that by forming a transparent resin layer containing a dry cured resin, an anti-glare film with further reduced white haze can be obtained. In Comparative Example 13 in which a resin that is not curable by drying is used in the transparent resin layer, the RΔq value is small and the anti-glare property is poor. As is evident from this, by forming a transparent resin layer using a dry cured resin, an anti-glare film having a better contrast ratio than an anti-glare film without any transparent resin layer while maintaining excellent anti-glare properties can be obtained. Can be.

Examples 27-31

The anti-glare film is obtained separately in substantially the same manner as in Examples 1 to 5, except that the amount of styrene fine particles is changed to 400 g.

Examples 32-35

The anti-glare film is obtained separately in substantially the same manner as in Examples 1 to 5, except that the amount of styrene fine particles is changed to 480 g.

Anti-glare properties

For each anti-glare film obtained as described above in Examples 1-5 and 27-35, the anti-glare properties were evaluated as follows.

Two fluorescent lamps are reflected from the surface of the anti-glare layer, and the visibility of the lamp's reflection is evaluated according to the following five criteria.

Level 5: Two fluorescent lamps are observed as single light and the shape of the lamp cannot be recognized.

Level 4: Two fluorescent lamps can be observed, but the shape of the lamp cannot be recognized.

Level 3: Two distinct fluorescent lamps and unclear edges of the lamp can be observed and the shape of the fluorescent lamp can be recognized.

Level 2: Two distinct fluorescent lamps can be clearly observed and the edges of the lamps can be observed.

Level 1: Two distinct fluorescent lamps can be clearly observed and the clear edges of the lamps can be recognized.

Particle filling ratio Coating thickness Level of anti-glare properties Example 1 5% 6 μm 5 Example 2 5% 8 μm 4 Example 3 5% 12 μm 3 Example 4 5% 15 μm 3 Example 5 5% 18 μm 2 Example 27 10% 6 μm 5 Example 28 10% 8 μm 4 Example 29 10% 12 μm 4 Example 30 10% 15 μm 3 Example 31 10% 18 μm 3 Example 32 12% 6 μm 5 Example 33 12% 8 μm 4 Example 34 12% 12 μm 4 Example 35 12% 15 μm 5

As can be seen from Table 2, when the particle filling ratio is greater than 10%, the dependence of the anti-glare property on the coating thickness is likely to be small, thereby making it difficult to control the anti-glare property by changing the coating thickness. do.

Next, see Table 3 and FIG. 7 for a correlation between white haze measured for anti-glare films with bonded black glass sheets and white haze measured for anti-glare films with bonded black acrylic sheets. Will be explained.

(Measured) white turbidity through glass sheet (Measured) white turbidity through acrylic sheet (Calculated) white turbidity through acrylic sheet Experimental Example 1 2.6 2.3 2.3 Experimental Example 1 2.0 1.8 1.7 Experimental Example 1 0.9 0.5 0.5 Experimental Example 1 0.9 0.6 0.5 Experimental Example 1 1.0 0.6 0.6 Experimental Example 1 1.0 0.6 0.6 Experimental Example 1 1.7 1.5 1.4 Experimental Example 1 1.2 0.8 0.9 Experimental Example 1 1.3 0.9 1.0 Experimental Example 1 1.1 0.7 0.7 Experimental Example 1 1.2 0.8 0.8 Experimental Example 1 1.0 0.6 0.6 Experimental Example 1 1.0 0.6 0.6 Experimental Example 1 0.9 0.4 0.5

For the anti-glare films in Experimental Examples 1 to 14 obtained by changing the white turbidity by appropriately controlling the thickness and the particle diameter in Example 1, the black glass sheet-bonded anti-glare film and the black acrylic sheet-bonded anti-glare The measurement results of the white haze on the film are reported in Table 3. In addition, numerical values determined by calculation using a regression line obtained from the correlation between the black glass sheet and the black acrylic sheet for the white haze for the anti-glare film through the acrylic sheet are recorded in Table 3. As can be seen from Table 3, values near the measured values can be obtained by calculation.

The regression line from the correlation between the black glass sheet and the black acrylic sheet is shown for the white haze for the black glass sheet bonded anti-glare film on the abscissa and for the black acrylic bonded anti-glare film on the ordinate as shown in FIG. Obtained by plotting white haze. In Fig. 7, when the white haze for the glass sheet-bonded anti-glare film is taken as x and the white haze for the acrylic sheet-bonded anti-glare film is taken as y, the regression line is represented by the following equation (2). :

y = 1.1039 x-0.4735 (2)

Is obtained, and the crystal coefficient R ² is 0.9909. From the above, it is found that there is a close correlation between the white haze when measured using the black glass sheet and the white haze when measured using the black acrylic sheet.

While the embodiments and examples of the present invention have been described in detail above, the present invention is not limited to the above embodiments and examples, and may be changed or modified based on the technical concept of the present invention.

For example, the numerical values described in the above embodiments and examples are merely examples, and different values from these may be used as desired.

In the first embodiment of the present invention described above, the embodiment in which the anti-glare film is used in the liquid crystal display device has been described, but the application of the anti-glare film is not limited to the liquid crystal display. The anti-glare film can be applied to various display devices such as plasma displays, electroluminescent displays, and cathode ray tube (CRT) displays.

According to an embodiment of the invention, an anti-glare film having both good anti-glare properties and good contrast ratio is produced by forming a Bernard cell in the surface of the anti-glare layer. Furthermore, according to the present invention, since the anti-glare film having both excellent anti-glare property and excellent contrast ratio is produced using a process in which the paint is applied to the substrate, the anti-glare film having high quality is produced at low cost. It is obtained with high productivity.

1 is a schematic cross-sectional view showing an example of the configuration of a liquid crystal display device in the first embodiment of the present invention.

2 is a schematic cross-sectional view showing an example of the configuration of an anti-glare film in the first embodiment of the present invention.

3 is a diagram illustrating a square mean slope.

4 is a schematic cross-sectional view showing an example of the configuration of an anti-glare film in a second embodiment of the present invention.

5 is a photograph of the surface of the anti-glare film in Example 1. FIG.

6 is a photograph of the surface of the anti-glare film in Comparative Example 5. FIG.

7 is a graph illustrating the correlation between white haze when measured using a black glass sheet and white haze when measured using a black acrylic sheet.

8 is a schematic cross-sectional view showing an example of the configuration of a conventional anti-glare film.

9 is a schematic cross-sectional view showing an example of the configuration of a conventional anti-glare film.

<Explanation of symbols for the main parts of the drawings>

1: anti-glare film

2: liquid crystal panel

2a, 2b: polarizing sheet

3: light source

11: description

12: anti-glare layer

13: fine particles

Claims (33)

Applying a coating material containing at least a resin, a solvent, and fine particles on the substrate; Drying the coating applied on the substrate and forming a Bernard cell structure on the surface of the coating layer by convection generated during volatilization of the solvent; Curing the resin contained in the paint having the Bernard cell structure formed thereon, and forming an anti-glare layer having a fine concavo-convex shape having a gentle curvature on the surface; The average film thickness at the time of drying of the said anti-glare layer is more than the average particle diameter of the said microparticle, 3 times or less of the average particle diameter of the said fine particle, The manufacturing method of the anti-glare film. The method for producing an anti-glare film according to claim 1, wherein the white haze obtained by irradiating diffused light to the surface of the anti-glare layer and quantifying the diffuse reflection component is 0 or more and 1.7 or less. The method of claim 1, wherein the fine particles are organic fine particles, The difference between the surface energy of the said organic fine particle and the surface tension of the said solvent is 8mN / m or more and 13mN / m or less, The manufacturing method of the anti-glare film. The method of claim 1, wherein the fine particles comprise styrene, The surface tension of the solvent is more than 0mN / m 23mN / m or less, characterized in that the anti-glare film production method. The method for producing an anti-glare film according to claim 1, wherein the fine particles comprise an acrylic styrene copolymer. The said acrylic styrene copolymer consists of 60 mass% or more and 90 mass% or less of styrene components, and 10 mass% or more and 40 mass% or less of acrylic components, The manufacture of the anti-glare film of Claim 5 characterized by the above-mentioned. Way. The method for producing an anti-glare film according to claim 1, wherein the filling ratio of the fine particles is 4% or more and 10% or less. The method for producing an anti-glare film according to claim 1, wherein in the drying of the paint, the fine particles are agglomerated mainly in the in-plane direction by convection generated during volatilization of the solvent. The method for producing an anti-glare film according to claim 8, wherein the anti-glare layer surface is covered with the aggregated fine particles by the resin. The said resin is an ionizing radiation-curable resin, a thermosetting resin, or their mixed resin, Comprising: The glare characterized by including at least 1 sort (s) of the monomer, oligomer, and polymer which are liquid after drying the said paint. A method of producing the prevention film. The method of manufacturing the anti-glare film according to claim 1, wherein in the curing of the resin, the resin is cured in a state where a Bernard cell structure is formed on the surface by irradiation or ionizing radiation. The method of claim 1, wherein the root mean square slope (RΔq) on the anti-glare layer surface is 0.003 to 0.05. The method of claim 1, wherein the fine particles are covered with a resin, and the fine particles do not protrude from the surface of the anti-glare layer. The method of claim 1, after the step of curing the resin, the step of applying a paint comprising at least a resin and a solvent on the anti-glare layer, And drying and curing the coating applied on the anti-glare layer, and forming a transparent resin layer on the anti-glare layer. The manufacturing method of the anti-glare film according to claim 14, wherein the paint applied on the anti-glare layer covers a convex portion of the surface of the anti-glare layer to reduce the inclination near the particles. The manufacturing method of the anti-glare film of Claim 14 in which the resin contained in the said coating material apply | coated on the said anti-glare layer contains the dry hardening resin which turns into a solid after drying. The resin of claim 14, wherein the resin included in the paint applied on the anti-glare layer comprises at least one of an ionizing radiation-curable or thermosetting monomer, oligomer, and polymer, In the forming step of the transparent resin layer, the resin is cured by irradiation or heating of ionizing radiation, characterized in that the anti-glare film production method. Materials and Having at least one anti-glare layer installed on the substrate, The anti-glare layer is coated with a resin, a solvent, and a paint containing at least fine particles on a substrate, drying the paint applied on the substrate, and applying by convection generated upon volatilization of the solvent. A Bernard cell structure is formed on the surface of the layer, and the resin contained in the paint having the Bernard cell structure is cured to form a film thickness of not less than the average particle diameter of the fine particles and not more than three times the average particle diameter of the fine particles. , Anti-glare film. The anti-glare film according to claim 18, wherein a white haze obtained by quantifying a diffuse reflection component by irradiating diffused light to a surface of the anti-glare layer is from 0 to 1.7. The method of claim 18, wherein the fine particles are organic fine particles, The anti-glare film whose difference in surface energy of the said organic fine particle and the surface tension of the said solvent is 8 mN / m or more and 13 mN / m or less. The method of claim 18, wherein the fine particles comprise styrene, The surface tension of the solvent is more than 0mN / m 23mN / m or less, anti-glare film. The anti-glare film according to claim 18 wherein the fine particles comprise an acrylic styrene copolymer. The anti-glare film according to claim 22, wherein the acrylic styrene copolymer is composed of 60% by mass or more and 90% by mass or less of a styrene component and 10% by mass or more and 40% by mass or less of an acrylic component. The anti-glare film according to claim 18, wherein the filling ratio of the fine particles is 4% or more and 10% or less. The anti-glare film according to claim 18, wherein the fine particles are agglomerated mainly in the in-plane direction by convection generated during volatilization of the solvent. 26. The antiglare film of claim 25 wherein said antiglare layer surface covers said aggregated fine particles with said resin. The anti-glare film according to claim 18, wherein the resin is an ionizing radiation-curable resin, a thermosetting resin, or a mixed resin thereof, and comprises at least one of monomers, oligomers, and polymers which are liquid even after the paint is dried. The anti-glare film according to claim 18, wherein the resin is cured in a state where a Bernard cell structure is formed on a surface by irradiation or heating of ionizing radiation. The antiglare film of claim 18 wherein the root mean square slope (RΔq) at the antiglare layer surface is from 0.003 to 0.05 μm. The anti-glare film of claim 18 wherein the fine particles are covered with a resin and the fine particles do not protrude from the surface of the anti-glare layer. With polarizer, Having an anti-glare film installed on the polarizer, The anti-glare film has a substrate and at least one anti-glare layer provided on the substrate, The anti-glare layer is a coating layer by applying convection generated upon volatilization of a solvent by applying a coating material containing at least a resin, a solvent, and fine particles on a substrate, and drying the coating applied on the substrate. The Bernard cell structure is formed on the surface, and the resin contained in the paint having the Bernard cell structure is cured to form a film thickness of not less than the average particle diameter of the fine particles and not more than three times the average particle diameter of the fine particles. , Anti-glare polarizer. A display unit for displaying an image, An anti-glare film provided on the display surface side of the display portion, The anti-glare film has a substrate and at least one anti-glare layer provided on the substrate, The anti-glare layer is a coating layer by applying convection generated upon volatilization of a solvent by applying a coating material containing at least a resin, a solvent, and fine particles on a substrate, and drying the coating applied on the substrate. The Bernard cell structure is formed on the surface, and the resin contained in the paint having the Bernard cell structure is cured to form a film thickness of not less than the average particle diameter of the fine particles and not more than three times the average particle diameter of the fine particles. , Display device. Materials and At least one optical layer provided on the substrate, The said optical layer apply | coats the coating material which contains resin, a solvent, and microparticles at least on a base material, dries the said coating material apply | coated on the said base material, and is applied to the surface of an application layer by convection which arises at the time of volatilization of a solvent. By forming a Bernard cell structure and hardening resin contained in the said coating material in which said Bernard cell structure was formed, it is formed in the film thickness more than the average particle diameter of the said microparticle, and 3 times or less of the average particle diameter of the said microparticle. film.

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